Browsing by Author "Yang, JC"

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    Cytokine gene polymorphisms and the outcome of invasive candidiasis: a prospective cohort study.
    (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2012-02) Johnson, MD; Plantinga, TS; van de Vosse, E; Velez Edwards, DR; Smith, PB; Alexander, BD; Yang, JC; Kremer, D; Laird, GM; Oosting, M; Joosten, LA; van der Meer, JW; van Dissel, JT; Walsh, TJ; Perfect, JR; Kullberg, BJ; Scott, WK; Netea, MG
    BACKGROUND:  Candida bloodstream infections cause significant morbidity and mortality among hospitalized patients. Although clinical and microbiological factors affecting prognosis have been identified, the impact of genetic variation in the innate immune responses mediated by cytokines on outcomes of infection remains to be studied. METHODS:  A cohort of 338 candidemia patients and 351 noninfected controls were genotyped for single-nucleotide polymorphisms (SNPs) in 6 cytokine genes (IFNG, IL10, IL12B, IL18, IL1β, IL8) and 1 cytokine receptor gene (IL12RB1). The association of SNPs with both candidemia susceptibility and outcome were assessed. Concentrations of pro- and antiinflammatory cytokines were measured in in vitro peripheral blood mononuclear cell stimulation assays and in serum from infected patients. RESULTS:  None of the cytokine SNPs studied were associated with susceptibility to candidemia. Persistent fungemia occurred in 13% of cases. In the multivariable model, persistent candidemia was significantly associated with (odds ratio [95% confidence interval]): total parenteral nutrition (2.79 [1.26-6.17]), dialysis dependence (3.76 [1.46-8.64]), and the SNPs IL10 rs1800896 (3.45 [1.33-8.93]) and IL12B rs41292470 (5.36 [1.51-19.0]). In vitro production capacity of interleukin-10 and interferon-γ was influenced by these polymorphisms, and significantly lower proinflammatory cytokine concentrations were measured in serum from patients with persistent fungemia. CONCLUSIONS:  Polymorphisms in IL10 and IL12B that result in low production of proinflammatory cytokines are associated with persistent fungemia in candidemia patients. This provides insights for future targeted management strategies for patients with Candida bloodstream infections.
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    What are Households Willing to Pay for Improved Water Access? Results from a Meta-Analysis
    (Ecological Economics, 2017-06-01) Van Houtven, GL; Pattanayak, SK; Usmani, F; Yang, JC
    © 2016Although several factors contribute to low rates of access to improved water and sanitation in the developing world, it is especially important to understand and measure household demand for these services. One valuable source of information regarding demand is the growing empirical literature that has applied stated preference methods to estimate households’ willingness to pay (WTP). Because it is difficult to generalize and support planning based on this scattered literature, we conduct a meta-analysis to take stock of the worldwide sample of household WTP for improved drinking water services. Using 171 WTP estimates drawn from 60 studies, we first describe this sample and then examine the potential factors that explain variation in WTP estimates. Our results suggest that households are willing to pay between approximately $3 and $30 per month for improvements in water access. Specifically, in line with economic theory and intuition, WTP is sensitive to scope (the magnitude of improvement in drinking water services), as well as household income, and stated-preference elicitation method. We demonstrate how our results can be used to predict household-level WTP for selected improvements in drinking water access in regions with low coverage, and find that private benefits exceed the cost of provision.